Latkes may be a Hanukkah favorite, but with beets and dill added to the potato mixture and a bright lemony yogurt sauce for serving, this version is equally suited for spring. And as long as you use matzo and not flour, they can be served at Passover.
Whisk the yogurt with the olive oil, 1/2 teaspoon salt, 1/4 teaspoon pepper and the lemon zest in a small bowl until smooth. Refrigerate until ready to serve.
Grate the potatoes and onion on the large holes of a box grater into a colander set over a bowl. Add 1 teaspoon salt and a few grinds of pepper, toss well and let stand 5 minutes. Squeeze handfuls of the mixture firmly with your hands to remove as much liquid as possible. Blot dry with paper towels, then transfer to a large bowl.
Add the beaten egg, grated beet, matzo meal or flour, dill and coriander to the potato mixture and toss well to combine. Scoop 1/4 cupfuls of the mixture and tightly pack into thin 3- to 4-inch pancakes. Transfer to a paper towel–lined baking sheet.
Preheat the oven to 250˚. Heat 1/4 inch vegetable oil or chicken fat in a large nonstick skillet over medium-high heat.
Working in three batches, fry the latkes until deep golden brown, 3 to 5 minutes per side, reducing the heat as needed if the latkes are browning too quickly. Remove to a rack set on a rimmed baking sheet and sprinkle with salt. Keep warm in the oven while you make the remaining latkes.